Polymer dispersed liquid crystal fiber optic electric field probe

1997 ◽  
Vol 46 (1) ◽  
pp. 31-35 ◽  
Author(s):  
B.M. Lacquet ◽  
P.L. Swart ◽  
S.J. Spammer
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Fiber Optic ◽  
Crystal Fiber ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed ◽  
Electric Field Probe

Liquid crystal fiber optic electric field probe

1995 ◽  
Author(s):  
Beatrys M. Lacquet ◽  
Pieter L. Swart ◽  
Stephanus J. Spammer
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Fiber Optic ◽  
Crystal Fiber ◽  
Electric Field Probe

scholarly journals Polymer Dispersed Cholesteric Liquid Crystals With a Toroidal Director Configuration under an Electric Field

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 732
Author(s):  
Anna P. Gardymova ◽  
Mikhail N. Krakhalev ◽  
Victor Ya. Zyryanov ◽  
Alexandra A. Gruzdenko ◽  
Andrey A. Alekseev ◽  
...  
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Electric Field ◽  
Point Defects ◽  
Structural Response ◽  
Optical Filters ◽  
Response Curves ◽  
Polymer Dispersed Liquid Crystal ◽  
Dichroic Dye ◽  
Polymer Dispersed

The electro-optical properties of polymer dispersed liquid crystal (PDLC) films are highly dependent on the features of the contained liquid crystal (LC) droplets. Cholesteric LC droplets with homeotropic boundaries can form several topologically different orientational structures, including ones with single and more point defects, layer-like, and axisymmetric twisted toroidal structures. These structures are very sensitive to an applied electric field. In this work, we have demonstrated experimentally and by computer simulations that twisted toroidal droplets reveal strong structural response to the electric field. In turn, this leads to vivid changes in the optical texture in crossed polarizers. The response of droplets of different sizes were found to be equivalent in terms of dimensionless parameters. In addition, the explanation of this phenomenon showed a comparison of theoretical and experimental structural response curves aids to determine the shape of the droplet. Finally, we demonstrated that the addition of a dichroic dye allows such films to be used as optical filters with adjustable color even without polarizers.

scholarly journals Accurate, Efficient and Rigorous Numerical Analysis of 3D H-PDLC Gratings

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3725
Author(s):  
Jorge Francés ◽  
Sergio Bleda ◽  
Daniel Puerto ◽  
Sergi Gallego ◽  
Andrés Márquez ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
High Performance ◽  
Fdtd Method ◽  
Polymer Dispersed Liquid Crystal ◽  
Optical Media ◽  
Polymer Dispersed ◽  
3D Numerical Modelling ◽  
Anchoring Strength ◽  
Split Field

This work presents recent results derived from the rigorous modelling of holographic polymer-dispersed liquid crystal (H-PDLC) gratings. More precisely, the diffractive properties of transmission gratings are the focus of this research. This work extends previous analysis performed by the authors but includes new features and approaches. More precisely, full 3D numerical modelling was carried out in all analyses. Each H-PDLC sample was generated randomly by a set of ellipsoid geometry-based LC droplets. The liquid crystal (LC) director inside each droplet was computed by the minimisation of the Frank elastic free energy as a function of the applied electric field. The analysis carried out considered the effects of Frank elastic constants K11, K22 and K33; the anchoring strength W0; and even the saddle-splay constant K24. The external electric field induced an orientation of the LC director, modifying the optical anisotropy of the optical media. This effect was analysed using the 3D split-field finite-difference time-domain (SF-FDTD) method. In order to reduce the computational costs due to a full 3D tensorial analysis, a highly optimised method for high-performance computing solutions (HPC) was developed. The influences of the anchoring and voltage on the diffraction efficiencies were investigated, showing the potential of this approach.

Effect of Host Polymer Matrices on Electro Optical and Dielectric Behaviour of Polymer Dispersed Liquid Crystal System

2012 ◽  
Vol 584 ◽  
pp. 531-535 ◽  
Author(s):  
Rajendra Deshmukh ◽  
Sanmesh Parab ◽  
Manoj Malik
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Methyl Methacrylate ◽  
Indium Tin Oxide ◽  
Dielectric Relaxation Spectroscopy ◽  
Sensitive Material ◽  
Poly Methyl Methacrylate ◽  
Polymer Dispersed Liquid Crystal ◽  
Liquid Crystal System ◽  
Polymer Dispersed

The effect on the electrical characteristics of poly (methyl methacrylate) (PMMA) and poly (methyl methacrylate – co – butyl acrylate) (PMMABA) containing liquid crystal (E8) as dispersed material, is investigated in terms of electro optical and dielectric relaxation spectroscopy (DRS) technique. This polymer dispersed liquid crystal (PDLC) composite film is sandwiched between two glass slides with a transparent conductive substrate such as indium tin oxide (ITO). The resulting assembly forms an electro-sensitive material that can be switched from a OFF state to a ON state by the application of an external electric field or thermal ramp. In the present investigation PMMA / E8, PMMABA / E8 and PMMA+PMMABA / E8 composite films of 30/70 wt / wt % were prepared by Solution Induced Phase Separation (SIPS) method. Morphological study showed that homogeneous LC phase is embedded in a spongy – like polymer matrix. Electro optical behavior was determined under the condition of an externally applied AC electric field (0-200Vp-p, 50-1000Hz). DRS has been carried out in the frequency range from 20 Hz to 20 MHz and over the temperature range from 24°C to 75°C.The interfacial charge layer effect and qualitative evaluation of distribution of relaxation time is characterized by Cole-Cole model.

scholarly journals Holographic Characteristics of Photopolymers Containing Different Mixtures of Nematic Liquid Crystals

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 325 ◽  
Author(s):  
Sandra Fenoll ◽  
Francisco Brocal ◽  
José David Segura ◽  
Manuel Ortuño ◽  
Augusto Beléndez ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Light Intensity ◽  
Electric Field ◽  
Diffraction Efficiency ◽  
Applied Voltage ◽  
Nematic Liquid Crystals ◽  
Variable Electric Field ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed

A holographic polymer dispersed liquid crystal (HPDLC) is used to record holographic diffraction gratings. Several mixtures of nematic liquid crystals (LC) are used as components of the HPDLC to evaluate their influence in static and dynamic basic properties. The diffraction efficiency obtained in the reconstruction of the holograms is evaluated to compare the influence of the different LC. Additionally, the samples are exposed to a variable electric field and the diffracted light intensity as a function of the applied voltage is measured to evaluate the influence of the LC. The results obtained show significant differences depending on the LC incorporated to the photopolymer.

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